Railway traffic controlling apparatus



4 Sheets-Sheet 1 INVENTOR.

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C. D. IHRIG RAILWAY TRAFFIC CONTROLLING APPARATUS Jan. 10, 1956 FiledMarch 22, 195.1

Jan.'10, 1956 c. D. IHRIG RAILWAY TRAFFIC CONTROLLING APPARATUS 4Sheets-Sheet 3 Filed March 22, 1951 C. D. IHRIG RAILWAY TRAFFICCONTROLLING APPARATUS Jan. 10, 1956 4 Sheets-Sheet 4 Filed March 22,1951 JJ AN r S E N swwm NN 2 M 58% INVENTOR. 0061/ d 0.112119: BY

H16 ATTORNEY United States Patent O RAILWAY TRAFFIC CONTROLLINGAPPARATUS Clifford D. Ihrig, Penn Township, Allegheny County, Pa.,

assignor to Westinghouse Air Brake ornpany, a corporation ofPennsylvania Application March 22, B51, Serial No. 216,953

Claims. (Cl. 246-46) My invention relates to railway traflic controllingapparatus. More particularly, my invention relates to apparatus of thetype which is known as traffic locking apparatus, by means of whichtrafiic governing devices such, for example, as signals, for any givenstretch of railway track, are, in part, manually controllable forgoverning traffic movements in both directions, and by means of whichthe traflic governing devices, after being controlled for governingtrafiic movements in one direction or the other over the stretch ofrailway track, cannot be controlled for governing trafiic movements inthe opposite direction while the stretch of track is occupied by atrain. One form of traflic locking apparatus, which has been used,requires joint action by persons at two ditferent control stations formanually controlling traflic movements in both directions over a stretchof railway track. Each of the two control stations may be provided withan interlocking machine, and each of the interlocking machines may beequipped with a trafiic lever which is mechanically interlocked with asignal lever which controls a signal for governing traffic movementsonto the corresponding end of the stretch of railway track.

In apparatus embodying my invention, no separate traffic levers areemployed. Instead, trafiic direction con trolling apparatus, in myinvention, is controlled by manually controllable signal relays whichalso control the signals forgoverning traiiic movements onto theopposite ends of the stretch of railway track.

In some forms of trafiic locking apparatus, a trafiic control circuitarrangement has been employed, which embodies two conductors extendingbetween the opposite ends of the associated stretch of railway track. Inthis control circuit arrangement, a plurality of polar traiiic controlrelays, one for each signal location,-are energized in series by currentof one polarity or the other. With such forms of traffic lockingapparatus, the associated stretch of railway track may be divided into aplurality of track sections, each of which is provided with a trackcircuit including the rails of the section, and a suitable source ofcurrent connected across the rails adjacent one end of the section, andalso including a neutral track relay connected across the rails adjacentthe opposite end of the section. A front contact of each of these trackrelays is included in the traffic locking circuit arrangement. Linecontrol circuits for the signals are controlled by contacts of the trackrelays and by contacts of the polar trafiic control relays.

In a later form of traflic locking apparatus, in which also a pluralityof polar trafiic control relays are energized in series in a trafficcontrol circuit, two track circuits, which may be of the coded type, areemployed for each track section, one for each direction of trafficmovement. The track circuits for a given direction of traflic movementare set up by contacts of the polar traflic control relays when closedin a given or normal position in response to energization of the polartrafiic control relays by current of a given normal polarity, and thetrack circuits for the opposite direction of traffic movement are set upby contacts of the polar traffic control relays when closed in theopposite or reverse position in response to energization of the polartrafiic control relays by current of the opposite or reverse polarity.It has been found that, with this later scheme, if contacts of the trackrelays or of relays controlled by the track relays are included in thetraffic control circuit arrangement similarly to the way they areincluded in the earlier schemes, a locked-out condition of the tratiiccontrol circuits may occur under some conditions. If, for example, thecontacts of one or more of the polar trafiic control relays shouldbecome misplaced by an induced surge of foreign current, one or moretrack relays would become deenergized, and the traific control circuitswould not be self-restoring.

An object of my invention is therefore the provision of means for makingthe misplacernent of the polar contacts of the polar traffic controlrelays in a series traffic control circuit less likely to occur.

A feature of my invention for attaining this object is the provision ofan arrangement for keeping the polar traflic control relays energizedwhile the associated stretch of railway track is occupied by a train, orwhile a signal is controlled to display a proceed indication for a trainto enter the associated stretch of railway track.

Another feature of my invention for attaining this object is theprovision of an arrangement for keeping the polar trafiic control relaysenergized, While the associated stretch of railway track is occupied bya train, by current of the same polarity as that by which they wereenergized when the train entered the stretch of track, and when a signalwas cleared for directing the train to enter the stretch of track.

Another object of my invention is the provision of means by which atraffic control circuit will be rendered self-restoring in the event ofthe polar contacts of one or more of the polar traffic control relayswhich are included in series in the traliic control circuit becomingmisplaced in some way such, for example, as by a surge of currentinduced from a foreign source of power while the traflic control circuitis deenergized.

A feature of my invention for attaining this object is the provision ofauxiliary means for closing a traffic control circuit in response tomisplacement of the polar contacts of a polar traflic control relay.

Still another object of my invention is the provision of means forrestoring the traiiic control circuit to an operative condition in theevent of a locked-out condition being caused by some unusual occurrence.

A feature of my invention for attaining this object is the provision ofan arrangement for restoring a traffic control circuit to an operativecondition by energization of the manually controllable signal relay forthe entering signal for either end of the associated stretch of track.

Another object of my invention is the provision of means for checkingthe condition of the trafiic controlling apparatus after each reversalof polarity of the current by which the tralfic control circuit isenergized.

A feature of my invention for attaining this object is the provision oftwo stick relays, one for each end of the stretch of track, each ofwhich can become energized only when the contacts of the polar traiiiccontrol relay for a signal adjacent the corresponding end of theassociated stretch of railway track are in the position for controllingthe apparatus to direct a train to enter the stretch of railway track atthat end, and only when the track circuits have been set up for a trainmoving onto the stretch of track in the corresponding direction, andalso only when the stretch of track is unoccupied. Each of the two stickrelays will then remain energized regardless of occupancy of the stretchof track by a train until the contacts of the polar traffic controlrelays are moved to the opposite position.

I shall describe one form of apparatus embodying my invention, and shallthen point out the novel features thereof in claims.

In the accompanying drawings, Figs. la, 1b, 1c and 1d, when placed endto end in the order named, with Fig. In on the left, constitute adiagrammatic view showing one form of apparatus embodying my inventionfor a stretch of railway track which is provided With a plurality ofsignals for governing trafiic movements in opposite directions over thestretch of railway track; which embodies a plurality of polar trafiiccontrol relays, one for each of given signal locations, connected inseries, each of the polar traific control relays having one or morecontacts which, when the corresponding relay becomes deenergized, remainclosed in the normal or the reverse position to which they were lastpreviously operated in response to current of normal or reversepolarity; in which two sources of current of similar potential, oneadjacent each end of the stretch of track, are connected in oppositionto each other in series with the polar traflic control relays, so

that the polar traffic control relays are normally not energized; inwhich operation of manually controllable signal control means for agiven end of the stretch of track effects energization of the polartraffic control relays by current of a given polarity from the source ofcurrent for the opposite end of the stretch, and operation of manuallycontrollable signal control means for the opposite end of the stretcheffects energization of the polar trafiic control relays by current ofthe opposite polarity from the source of current at the given end of thestretch; in which the polar trafiic control relays are retainedenergized by current from one or the other of the two sources of currentWhile the stretch of track is occupied by a train; and in which thesignals for a given direction of traffic movements are controlled bymeans including contacts of the polar traflic control relays closed in agiven normal position, and the signals for the opposite direction oftraflic movements are controlled by means including the contacts of thepolar trafiic control relays closed in the opposite or reverse position.

Similar reference characters refer to similar parts in the drawings.

Referring to the drawings, a stretch of main railway track X is shownconnected, adjacent one of its ends, with an auxiliary track U, by aswitch designated by the reference character 1, and is shown connected,at its opposite end, with a second auxiliary track, designated by thereference character Z, by a second switch designated by the referencecharacter 5.

The stretch of track X is divided by insulated joints 7, in the trackrails 9 and 911, into sections designated by the reference charactersa-b, bc, c-d, de and e-g. Each of the sections a-b and eg is providedwith a single track circuit including a suitable source of current such,for example, as a battery 8, connected across the rails adjacent one endof the section, and a traffic responsive track relay, designated by thereference character ITR r STR, respectively, connected across the railsadjacent the opposite end of the section. Each of the relays lTR and STRis normally energized by current from the corresponding track battery 8,but becomes deenergized in re sponse to a train on the correspondingsection of track.

Each of the sections b-c, cd and de is provided with two track circuits,one for each direction of traiiic movements. I shall assume that thedirection from left to right, as shown in the drawings, is eastbound,and therefore the opposite direction from right to left is westbound.Accordingly, the track circuit for eastbound trafiic movements over eachof the sections b-c, cd and de includes a suitable source of currentsuch, for examples, as a battery 8, connected at times across the railsadjacent the east end of the section, and a traflic responsive trackrelay, designated by the reference character TR with a distinguishingprefix, connected at times across the rails adjacent the West end of thesection. The

track circuit for the westbound traffic movements over each of thesections bc, 0-01 and de includes one of the batteries 8 connected attimes across the rails adjacent the west end of the section, and atraffic responsive track relay TR connected at times across the railsadjacent the east end of the section.

The track circuits shown for sections b-c, c-d and de are of the codedtype. Current supplied to each of the track circuits for these sectionsfrom the corresponding track battery 8 is at times controlled by acontact 10 of a code transmitting device, designated by the referencecharacter 75CT, and is at other times controlled by a contact 11 of acode transmitting device, designated by the reference character CT.

The control element of each of the code transmitters 75CT and ISGCT isconstantly connected across the terminals B and N of a suitable sourceof current such, for example, as a battery Q shown in Fig. 1b. Contact10 of each of the code transmitters 75CT is therefore repeatedly closedand opened at a predetermined frequency such, for example, as 75 timesper minute, and contact 11 of each of the code transmitters ISGCT isrepeatedly closed and opened at a second predetermined frequency such,for example, at 180 times per minute.

The track relays for each of the track circuits for sections l2c, c-dand a'e are of the code following type, and therefore these relaysrepeatedly close their contacts at their front and back pointsalternately at a frequency of 75 or 180 times per minute according asthe control elements of these relays are energized by current of the 75or 180 code frequency, respectively, from the corresponding trackcircuit.

The eastbound and westbound track circuits for each of the tracksections b-c, cd and d-e are selectively controlled by polar contacts ofpolar traflic control relays, each of which is designated by thereference character FR preceded by a suitable distinguishing prefix, sothat only one of the track circuits is prepared at any given time foreach of these track sections. The track relay for each of these tracksections becomes deenergized in response to a train on the correspondingtrack section.

Signals designated by the reference characters RAZ, RB2 and R4 governeastbound traffic movements over the stretch of track, and a signaldesignated by the reference character R6 governs eastbound trafiicmovements leaving the stretch of track. Signals designated by thereference characters LA6, L136 and L3 govern Westbound trafi'icmovements over the stretch of track shown, and signal L2 governs trafficmovements off of the stretch of track. The signals may be of anysuitable design such, for example, as the color light type, comprising agreen or clear proceed lamp G, a yellow or caution proceed lamp Y, and ared or stop lamp R, as shown in the drawings.

A polar traffic control relay, designated by the reference character AFRor DFR, is provided adjacent the location of each of the pairs ofsignals RA2 RB2, and LA6LB6, respectively, at opposite ends of thestretch of track, and a polar tralfic control relay, designated by thereference character BFR or CFR, is provided for each of the signals L3and R4, respectively, which govern traflic movements over the stretch oftrack between the pairs of signals RA2RB2 and LA6LB6. Relays AFR, BFR,CPR and DFR are connected in series with each other in a trafiic controlcircuit path which extends between relays AFR and DFR.

A suitable source of current such, for example, as a battery designatedby the reference character IQ, is connected to the west end of thistraffic control circuit path in opposition to a second suitable sourceof current of similar potential such, for example, as a battery 2Q,which is connected to the east end of this traffic control circuit path.Since the. batteries IQ and 2Q are of similar potential, but of oppositepolarity, the polar tratlic control relays AFR, BFR, CPR and DFR arenormally not energized,

' In order to prevent the passage of current over: this traffic controlcircuit path from either of the batteries 1Q or 2Q if there should be adifference of potential between these two batteries, a first asymmetricunit, designated by the reference character ii, is connected in serieswith battery 1Q at the west end of this traffic control circuit path,and a second asymmetric unit, designated by the reference character 21',is connected in series with battery 2Q at the east end of the tratficcontrol circuit path, with the low resistance direction of the twoasymmetric units in opposition to each other. Asymmetric units 1i and21' may be of any suitable design such, for example, as the well-knownhalf-wave copper oxide rectifier type.

A first traffic locking relay, designated by the reference characterRFL, is connected in series with battery 1Q at the west end ofthe'traflic control circuit path referred to, and a second trafficlocking relay, designated by the reference character LFL, is connectedin series with battery 2Q at the east end of the traflic controlcircuitpath.

Since there is normally no current flowing between batteries IQ and 2Q,relays RFL and LFL are normally deenergized.

First and second tratfic locking repeater relays, designated by thereference characters RFLP and LFLP, respectively, are controlled byrelays RFL and LFL, respectively. Each of the relays RFLP and LFLP ismade slow releasing by a resistor, designated by the reference characters, and an energy storing device such, for example, as a capacitor,designated by the reference character t, connected in series with eachother around the winding of each of these relays.

Operated in conjunction with switches 1 and 5 are switch circuitcontroller contacts designated by the reference characters IWC and 5WC,respectively. Each of these switch circuit controller contacts is closedin a normal position, when the corresponding switch is in its normalposition, as shown in Figs. 1a and 1d, and is closed in a reverseposition, when the corresponding switch is in the reverse position. 7

A normalswitch indication relay, designated by the reference characterINWC, is controlled by contact lWC in the normal position, and a reverseswitch indication relay, designated by the reference character lRWC, is

' Controlled by contact IWC in its reverse position. Normal and reverseswitch indication relays SNWC and SRWC are similarly controlled bycontact SWC in its normal and reverse positions, respectively.

Signals L2 and R6 are controlled by means including home signal relaysdesignated by the reference characters L2H and R6H, respectively. RelayL2H may be controlled by means including a manually operable devicesuch, for example, as a lever LZV, and by track relay lTR. Relay R6H maybe similarly controlled by means including a manually operable devicesuch, for example, as a lever RoV, and by track relay STR.

A manually controllable signal relay RZHS for signals RA2 and R82 isshown controlled by a manually operable device such, for example, as alever RZV, and by relays RFLP and ITR. A manually controllable signalrelay Lei-IS for signals LAo and LE6 is similarly controlled by a leverLoV and by relays LFLP and STR.

Instead of being controlled by direct wire circuits, as shown in theaccompanying drawings, relays RZHS and L6HS may be controlled by aselective code system such, for example,,as that shown in Letters Patentof the United States No. 2,229,249, issued January 21, 1941, to Lloyd V.Lewis, for Remote Control Systems.

Each of the levers LZV, REV, L6V and R6V has a normal position n, inwhich it is shown in the drawings, and has also a reverse position 1 tothe left, and a reverse position r to the right, as shown in thedrawings. Each of the levers RZV and L6! is biased toward its n positionby suitable means which may, for example, be springs designated by thereference characters in and m connected between each of these levers andfixed blocks fp and rp, respectively.

Afirst route relay, designated by the reference character RZHSP, forsignals RA2 and RBZ, is controlled by the manually controllable signalrelay RZHS, and by switch indication relays INWC and lRWC, and also by ablock repeater relay designated by the reference character RBP. A secondroute relay, designated by the reference character L6HSP, for signalsLA6 and LE6, is similarly controlled by the manually controllable signalrelay L6HS and by switch indication relays SNWC and SRWC, and also by ablock repeater relay designated by the reference character LBP.

A normal and a reverse traflic control repeater relay, designated by thereference characters LFP and REP, respectively, with a distinguishingprefix which is the same as that in the reference character for thecorresponding polar traffic control relay, are controlled by meansincluding a contact of the corresponding polar traffic control relay inthe normal and reverse positions, respectively. Each code followingtrack relay is in turn selectively controlled by contacts of one or bothof the trafiic control repeater relays for the corresponding polartratfic control relay. Each of the relays ARFP and DLFP is made slowreleasing by an asymmetric unit 31' or 4i, respectively, connectedacross its control winding.

Each of the code following track relays, in conjunction with a decodingtransformer, designated by the reference character F with adistinguishing prefix, controls a home decoding relay, designated by thereference character HR with a distinguishing prefix which is the same asthat in the reference character for the corresponding code followingtrack relay. Each of the code following track relays, in conjunctionwith the corresponding decoding transformer and a decoding unit,designated by the reference character ISt'DU, also controls a distantdecoding relay, designated by the reference character D with adistinguishing prefix which is the same as that in the referencecharacter for the corresponding code following track relay. Because ofthe decoding unit ISllDU, each distant decoding relay becomes operatedin response to energization of the corresponding track relay by codedcurrent of only a frequency of pulses per minute. Each home decodingrelay, however, becomes operated in response to energization of thecorresponding track relay by coded current of either 75 or 180 pulsesper minute. Each home decoding relay, and each distant decoding relay,on account of being controlled by a track relay, is a traffic responsiverelay, and becomes deenergized in response to deenergization of thecorresponding track relay by a train.

Signal RA2 is controlled by a home signal relay, designated by thereference character RAZH, and by the traffic responsive distant decodingrelay designated by the reference character RZD. Signal RBZ iscontrolled, similarly to signal RA2, by a home signal relay, designatedby the reference character RBZH, and by the distant decoding relaydesignated by the reference character R2D. The circuits for lighting thelamps of signal RBZ are similar to the circuits shown for lighting thelamps of signal RA2, and are accordingly omitted from the drawings.Signals LA6 and LE6 are controlled, similarly to signals RA2 and R132,respectively, by home signal relays designated by the referencecharacters LA6H and LB6H, respectively, and by the traiiic responsivedistant decoding relay designated by the reference character L'6D.

The relays RAZH and RBZH are controlled by the switch indication relayslNWC and IRWC, respectively, and by route relay RZHSP and home decodingrelay RZHR. Relays LAoI-I and LBoH are similarly controlled by switchindication relays SNWC and SRWC, respectively, and by route relay L6HSPand home decoding relay Lei-IR.

A first or eastbound traflic indication relay, designated by thereference character RFK, is controlled by relays lTR, RZHS and R21). Bymeans of a resistor sk and an energy storing device such, for example,as a capacitor tk, relay RFK is made slow releasing while relay lTR isenergized. When relay LTR becomes deenergized, however, resistor sk andcapacitor tk are disconnected from one of the terminals of relay RFK,and therefore do not make relay RFK slow releasing. A second orwestbound traffic indication relay, designated by the referencecharacter LFK, is controlled similarly to relay RFK.

A first or eastbound block repeater relay, designated by the referencecharacter RBP, is controlled by relays ARFP and R2D. A second orwestbound block repeater relay, designated by the reference characterLBP, is controlled by relays DLFP and L6D.

A first locking stick relay, designated by the reference character RAZS,and associated with signals RAZ and RB2, is controlled by relays RZHSP,RBZH, RAZH and 1TR, and also by a time element device, shown as a relay,designated by the reference character 2TB. Time element relay 2TE iscontrolled by a back contact of relay RAZS, as well as by relays RZHSP,RBZH and RAZH. A second locking stick relay, designated by the referencecharacter LAGS, associated with signals LA6 and LE6, is controlledsimilarly to relay RAZS.

Having described, in general, the arrangement and control of theapparatus shown by the accompanying drawings, I shall now describe, indetail, its operation.

As shown by the drawings, the contacts of the polar trafiic controlrelays AFR, BFR, CPR and DFR are in the normal position for preparingthe apparatus for controlling the signals for directing a westboundtraific movement over the stretch of track shown in the drawings;

signal L3 is displaying a yellow or caution indication, and

all other signals are displaying a red or stop indication; track relayslTR and STR are energized, track relay L3TR is energized by codedcurrent of the 75 code frequency, track relays R4TR and L6TR areenergized by current of 180 code frequency, and track relay RZTR isdeenergized; each of the switches 1 and 5' is in the normal position;each of the levers L2V, R2V, L6V and RdV is in its 11 position; each ofthe relays lNWC, SNWC, ALFP, BLFP, CLFP, DLFP, LSHR, R EHR, LGHR, R41),LD, RA2S,

LAGS, LFK and LBP is energized; and each of the relays.

passing from terminal B, through the back point of contact 1&9 of relayL2H, and lamp R of signal L2, to terminal N.

Relay lNWC is energized by a circuit passing from terminal B, throughswitch circuit controller contact 1WC in its normal position, and thewinding of relay lNWC to terminal N. Relay SNWC is shown energized inFig. ld by a circuit which is similar to the circuit just described forrelay lNWC.

Relay ALFP, shown in Fig. 1a is energized by a stick circuit passingfrom terminal B, through contact 12 of relay AFR closed in the normalposition, contact 13 of relay ARFP, contact 14 of relay ALFP, and thewinding of relay ALFP to terminal N. Relay ALFP will remain energized bythis stick circuit until contact 12 of relay AFR becomes operated to thereverse position in response to energization of relay AFR by current ofreverse polarity.

Relay BLFP, shown in Fig. 1b, is energized by a circuit passing fromterminal B, through contact 16 of relay BFR closed in the normalposition, contact 17 of relay BRFP, and the winding of relay BLFP toterminal N. Relay CLFP, shown in Fig. 1c, is energized by a circuitwhich is similar to the circuit just described for relay BLFP. RelayDLFP, shown in Fig. id, is energized by a circuit passing from terminalB, through contact 20 of relay DFR closed inthe normalposition, contact21-. of relay DREP,

and. the winding of. relay DLFP in multiple with ymmetric unit 4i toterminalN.

Relay RAZS, shown in Fig. la, is energized by a stick circuit passingfrom terminal B, through contacts 22, 23 and 24 of relays RZHSP, RBZHand RA2H, respectively, front point of contact 25 of relay RAZS, and thewinding of relay RAZS to terminal N.

Relay LA6S, shown in Fig. 1d, is energized by a similar stick circuitpassing from terminal B, through contacts 28, 29 and 39 of relays L6HSP,LB6H and LA6H, respectively, front point of contact 31 of relay LA6S,and the winding of relay LA6S to terminal N.

Track relay L3TR, shown in Fig. lb is energized by a circuit passingfrom battery 8 adjacent code transmitter CT, shown in Fig. 1a, throughcontact 19 of this code transmitter 75CT, back point of contact 34 ofrelay L2H, contact 35 of relay ALFP, back point of contact 36 of relayARFP, conductor 37, rail 9 of track section bc, front point of contact38 of relay BLFP, shown in Fig. 1b, winding of relay L3TR, front pointof contact 39 of relay BLFP, rail of track section b--c, conductor 40,and the back point of contact 41 of relay ARFP, back to battery 8. Withrelay L3TR thus energized by current of 75 code frequency, its contacts42 and 43 are repeatedly closing at their front and back pointsalternately at a frequency of 75 times per minute.

Current therefore passes from terminal B, through the front point ofcontact 42 of relay LSTR, and in a given direction through the centralportion of primary winding m of transformer 3F to terminal N, whilecontact 42 is closed at its front point, and then while contact 42 isclosed at its back point, current passes from terminal B, through theback point of contact 42, lower portion of primary winding m oftransformer 3F, in the opposite direction, to terminal N. Alternatngcurrent is thereby generated in secondary winding y of transformer 3F,and is rectified by contact 43 of relay L3TR for energizing relay L3HR.Current of the 75 code frequency cannot pass through the adjacentdecoding unit 180DU, and therefore relay L31) remains deenergized.

With relays L3HR and BLFP energized, and relay LSD deenergized, lamp Yof signal L3 is lighted by a circuit passing from terminal B, throughthe front point of contact 104 of relay L3HR, front point of contact ofrelay BLFP, back point of contact 196 of relay L313, and lamp Y ofsignal L3 to terminal N.

Relay R4T'R, shown in Fig. 1c, is energized by current of codefrequency, passing from battery 8 shown adjacent code transmitter 1841GTin Fig. lb, through contact 11 of code transmitter liifiCT, back pointof contact 44 of relay BRFB, front point of contact 45 of relay LSHR,front point of contact 46 of relay BLFP, rail 9 of section c-z1, frontpoint of contact 47 of relay CLFP, winding of relay R4TR, front point ofcontact 48 of relay CLFP, rail 9:: of section c-a', and front point ofcontact of relay BLFP, back to battery 8.

With relay R4TR thus energized by coded current, relay R4HR is energizedsimilarly to relay L3HR, as previously described. With relay R ETRenergized by current of 180 code frequency, the corresponding decodingunit 139331] permits relay R41) to also be energized. Although relaysR4HR and R4D are both energized, relay CRFP is deenergized, andtherefore red lamp R of signal R4 is lighted by a circuit passing fromterminal B, through the front point of contact 137 of relay R4HR, backpoint of contact 138 of relay CRFP, and lamp R of signal R4 to terminalN.

Relay L6TR, shown in Fig. id, is energized by current passing frombattery 8 shown adjacent the code transmitter 180CT in Fig. lc, throughcontact 11 of code transmitter lfitiC'l, front point of contact 52 ofrelay 114D, front point of contact 53 of relay CLFP, front point ofcontact 54 of relay RAHR, front point of contact 55 of relay CLFP, rail9 of section de, front point of contact 56 of relay DLFP, the winding ofrelay L6TR, front point of contact 57 of relay DLFP, rail 9a of sectiond--e, and front point of contact 58 of relay CLFP, back to battery 8.

With relay L6TR thus energized by current of the 180 code frequency,primary winding m of transformer 6F is energized by a circuit passingfrom terminal B, through contact 59 of relay DFR, and contact 60 ofrelay L6TR closed alternately at its front and back points, to terminalN. Relay L6HR will therefore be energized similarly to relay LSHR,previously described. Relay L6D will also be energized.

. With relays DLFP and L6D energized, relay LBP, shown in Fig. 1d, isenergized by its pickup circuit passing from terminal B, throughcontacts 68 and 69 of relays DLFP and L6D, respectively, and the windingof relay LBP to terminal N. A stick circuit for relay LBP is alsoclosed, which is the same as the pickup circuit just traced, except thatit includes contact 70 of relay LBP instead of contact 69 of relay L6D.

. Relay LFK is energized by a pickup circuit passing from terminal B,through contact 62 of relay L6D, back point of contact 63 of relay L6HS,contact 66 of relay STR, and the winding of relay LFK to terminal N. Aresistor sk and a capacitor zk are connected in multiple with thewinding of relay LFK by a path which includes the front point of contact67 of relay STR.

Red lamp R of signal LA6 is lighted by a circuit passing from terminalB, through the back point of contact 101 of relay LA6H, and lamp R ofsignal LA6 to terminal N. Lamp R of signal R6 is lighted by a circuitpassing from terminal B, through the back point of contact 163 of relay.R6H, and lamp R of signal R6 to terminal N.

stick circuit passing from terminal 13, through contact 73 of lever L6V,which is closed by lever L6V in its n or its 7 position or at any pointbetween these two positions, contact 74 of relay STR, contact 75 ofrelay L6HS, and the winding of relay L6HS to terminal N. Since lever1.6V is biased to its n position, as previously described, it willreturn to that position as soon as it is released by the leverman ordispatcher. Contact 71 of lever L6V will therefore open the pickupcircuit traced for relay LGHS, which will, however, remain energized byits stick circuit.

With relay L6HS energized, a circuit will be completed for energizingpolar trafiic control relays AFR, BFR, CPR and DFR by current of normalpolarity, this circuit passing from battery 1Q, shown in Fig. la,through contact '76 of relay 1T R, winding of relay RFL, contact '77 ofrelay RAZS, asymmetric unit 1i, back point of contact 78 of relay RZHS,front point of contact 79 of relay ALFP, winding of relay AFR, conductor80, winding of relay BFR, conductor 81, winding of relay CFR, conductor32, winding of. relay DFR, back point of contact 83 of relay DRFP, frontpoint of contact 84 of relay LFK, front point of contact 85 of relayL6I-IS, jumper 86, front point of contact 87 of relay L6HS, front pointof contact 38 of relay LFK, back point of contact 89 of relay DRFP,conductor 94), front point of contact B1 of relay ALFP, and the backpoint of contact 92 of relay RZHS to terminal 1N of battery 1Q. Thecontacts of the polar traffic control relays AFR, BFR, CPR and DFR arealready in the normal position, and will therefore not be moved inresponse to energization of these relays by current of normal polarity.

The westbound track circuits will therefore remain set up as previouslyprepared when the contacts of relays AFR, BFR, CPR and DFR werepreviously moved to the normal position, as shown in the accompanyingdrawings.

The route relay L6HSP will, however, now be energized by a circuitpassing from terminal B, through contacts )3 and 94 of relays LBP andL6HS, respectively, front point of contact 95 of relay 5NWC, back pointof contact B6 of relay SRWC, and the winding of relay LGHSP to terminalN. Relay L6HSP, upon becoming energized, opens its contact 28, therebydeenergizing relay LA6S. Relay L6HSP, however, upon becoming energized,completes a circuit for energizing relay LA6H, this circuit passing fromterminal B, through contacts 97, 98, 99 and 100 of relays L6HR, STR,LHSP and SNWC, respectively, and the winding of relay LA6H to terminalN.

Relay LA6H, upon becoming energized, picks up its contact 36, andthereby opens the circuit for relay LAGS at a second point. With relaysLA6H and L6D energized, green lamp G of signal LA6 will be lighted by acircuit pasing from terminal B, through the front point of contact 101of relay LA6H, front point of contact 102 of relay L61), and lamp G ofsignal LA6 to terminal N.

The pickup circuit for relay LFK, previously traced through contact 62of relay L6D, will now be opened at the back point of contact 63 ofrelay LGHS, but a second pickup circuit will be completed for relay LFK,which is the same as the pickup circuit previously traced except that itincludes the front point of contact 63 of relay L6HS instead of contact62 of relay L6D and the back point of contact 63 of relay Idol-IS.

With current now supplied from battery 1Q through the winding of trafiiclocking relay RFL to the traffic control circuit, relay RFL will beenergized, and therefore traflic locking repeater relay RLFP will alsobe energized, by a circuit passing from terminal B, through contact 103of relay RFL, and the winding of relay RFLP in multiple with a resistors and a capacitor 1, to terminal N.

Relay RFLP, upon becoming energized, opens its contact 111 in the pickupcircuit for relay RZHS. Therefore, as long as the trafiic controlcircuit is energized by current from battery 1Q passing through theWinding of relay RFL, relay RZHS cannot be energized for arranging theapparatus for controlling an eastbound trafiic movement over the stretchof track.

If, now, the leverman or dispatcher should decide to hold the westboundtrain at signal LA6, he will move lever L6V to its r position, therebyopening its contact 73 in the stick circuit for relay L6HS, and causingrelay L6HS to be deenergized. With relay L6HS deenergized, relay LtSHSPwill, in turn, be deenergized, which will cause relay LA6H to also bedeenergized.

With relay LA6H deenergized, lamp G of signal LA6 will becomeextinguished, and lamp R of this signal will again be lighted, aspreviously described. With relays LGHSP and LA6H now deenergized, timeelement relay 6TB will be energized by a circuit passing from terminalB, through contacts 28, 29 and 39 of relays Lei-1S1 LB6H and LAH,respectively, back point of contact 31 of relay LA6S, and the winding ofrelay 6T5 to terminal N.

Relay LA6Scannot become energized until a pickup circuit is completedfor this relay by relay 6TB uponthe lapse of a predetermined period oftime. Therefore, a circuit for energizing the polar trafiic controlrelays by current of reverse polarity passing from battery 2Q, throughcontact 11a of relay LA6S, could not at once he completed, if an attemptwere made to do so by effecting energization of relay RZHS.

If, before relay 6TB has closed its contact 32 in a pickup circuit forefiecting energization of relay LA6S, the westbound train has enteredsection e--g, relay LFK will be deenergized at contact 66 of relay STR,and then the circuit for energizing relays AFR, BFR, CPR and DFR bycurrent of reverse polarity could not be completed, because contacts 84and 88 of relay LFK 11 would be, open at their front point. Relay LA 6Swould, however, then be energized by a pickup circuit passing fromterminal B, through contacts 28, 29 and 30 of relays L6HSP, LB6H, andLA6H, respectively, contact 33 of relay STR, and the winding of relayLA6S to terminal N.

If, however, the westbound train does not enter section e-g, a secondpickup circuit for relay LA6S will be completed by relay 6TB, upon thelapse of a predetermined period of time, this circuit being the same asthe pickup circuit previously traced for relay LA6S except that itincludes contact 32 of relay 6TB instead of contact 33 of relay STR.Either the circuit previously traced for energizing relays AFR, BFR, CPRand DFR by current of normal polarity, or a circuit for energizing theserelays by current of reverse polarity, could then be completed.

I shall assume that the leverman or dispatcher now again effectsenergization of the polar traffic control relays by current of normalpolarity and the lighting of lamp G of signal LA6 by moving lever L6V toits f position for energizing relay L6HS. A westbound train, uponentering section eg, deenergizes relay STR, so that contact 66 of relaySTR opens the circuit for relay LFK, as previously described.

Contact 67 of relay STR also opens the path through resistor sk andcapacitor tk which is in multiple with the winding of relay LFK, andtherefore relay LFK will release quickly. Contact 67 of relay STR, uponbecoming closed at its back point, completes a circuit for dischargingcapacitor tk, this circuit passing from capacitor tk, through resistorsic, and back point of contact 67 of relay STR, back to capacitor tk.

Relay STR, upon becoming deenergized, also opens, at its contact 74, thestick circuit for relay L6HS, causing relay L6HS to become deenergized,which in turn causes relays L6HSP and LA6H to be deenergized. Relay LA6Swill now become energized by its first pickup circuit, previouslytraced, which includes contact 33 of relay STR. With relay LA6Hdeenergized, lamp R of signal LA6 will again be lighted.

With relay LFK deenergized, relays AFR, BFR, CPR and DFR will beretained energized by current of normal polarity, although relay L6HS isdeenergized. The circuit for retaining the polar traffic control relaysenergized by current of normal polarity is the same as the circuitpreviously traced for energizing these relays by current of normalpolarity except that it includes the back points of contacts 84 and 88of relay LFK instead of the front points of these contacts and the frontpoints of contacts 85 and 87 of relay L6HS.

When the train enters section d-e, relay L6TR will be deenergized,causing relays L6HR and L6D to also be deenergized. The pickup circuitfor relay LBP will now be open at contact 69 of relay L6D, but relay LBPwill be retained energized by its stick circuit previously traced, whichwill remain closed until relay DFR becomes energized by current ofreverse polarity and thereby deenergizes relay DLFP, causing contact 68of relay DLFP to be opened.

When the train leaves section e-g, relay STR will again becomeenergized. Relay LFK will, however, remain deenergized, because contact62 of relay L6D will still be open.

When the train enters section c-d, relay R4TR will become deenergized,causing relays R4HR and R4D to also be deenergized.

When the train leaves section d-e, relays R4HR and R4D will remaindeenergized while relay R4TR remains deenergized because of the trainoccupying section c-d. On account of relay CRFP being deenergized, itscontact 164 will be open, and therefore current of the 75 codefrequently cannot be supplied to section d,e through the back point ofcontact 54 of relay R4HR. Relay L6TR willtherefore remaindeenergizedwhile sec- 12 tion c d is occupied, although section d-e is unoccupied.

When the train enters section b-c, relay L3TR will become deenergized,causing relay L3HR to also, in turn, become deenergized. Relay L3HR,upon becoming deenergized, extinguishes lamp Y of signal L3, andcompletesa circuit for energizing lamp R of signal L3, this circuitpassing from terminal B, through the back point of contact 104 of relayL3HR, and lamp R of signal L3 to terminal N.

On account of the polar traffic control relays remaining energized bycurrent of normal polarity passing through the back points of contacts84 and 88 of relay LFK while the stretch of track is occupied by awestbound train between signals LA6 and L2, the contacts of the polartraffic control relays are less likely to be misplaced in some way such,for example, as by a surge of induced current, than if the polar trafficcontrol relays were deenergized While the stretch of track is occupied.If, however, the contacts of any of the polar traflic control relaysAFR, BFR, CPR and DER should become misplaced because of thecorresponding relay becoming energized by induced current of reversepolarity due to a surge of current while track X is occupied by awestbound train between signals LA6 and L2, such misplaced contactswould be restored to the normal position as soon as the surge of inducedcurrent ended.

When the train leaves section ca', relay R4TR will become energized bycurrent of the 75 code frequency passing from battery 8 at signal L3,through contact 10 of code transmitter 75CT at signal L3, contact 165 ofrelay BLFP, back point of contact of relay L3HR, front point of contact46 of relay BLFP, rail 9 of section cd, front point of contact 47 ofrelay CLFP, winding of relay R4TR, front point of contact 48 of relayCLFP, rail 9a of section c-d, and front point of contact 49 of relayBLFP, back to battery 8. With relay R4TR thus energized by coded currentof the 75 code frequency, relay R4HR will become energized, aspreviously described, but relay 'R4D will remain deenergized.

Relay L6TR will then be energized by current of the 75 code frequencypassing from battery 8 at signal R4, through contact 10 of codetransmitter 75CT at signal R4, back point of contact 52 of relay R iD,front point of contact 53 of relay CLFP, front point of contact 54 ofrelay R4HR, front point of contact 55 of relay CLFP, rail 9 of sectiond-e, front point of contact 56 of relay DLFP, the winding of relay L6TR,front point of contact 57 of relay DLFP, rail 9a of section de, and thefront point of contact 58 of relay CLFP, back to battery 8 at signal R4.With relay L6TR energized by current of the code frequency, relay L6HRwill also be energized, but relay L6D will remain deenergized.

On account of relay LBP being stiil energized by its stick circuit, theleverman or disaptcher could, if he so desired, now control signal LA6to display the yellow indication for a second westbound while the firstwestbound train occupies the stretch of track between signals L3 and L2.To do this, the leverman or dispatcher would move lever L6V to itsposition for effecting energization of relay L6HS as previouslydescribed. Relay LG'rISP, and, in turn, relay LA6H would then becomeenergized. Relay LA6H, upon becoming energized, would open, at the backpoint of its contact Mil, the circuit for lamp R of signal LA6, causingthis lamp to be extinguished, and would then complete a circuit forlighting lamp Y, this circuit passing from terminal B, through the frontpoint of contact 101 of relay LA6H, back point of contact 102 of relayL6D, and lamp Y of signal LA6 to terminal N.

In order to control signal L2 to display a proceed indication for thefirst westbound train, the leverman or dispatcher may move lever L2V toits position, thereby completing an energizing circuit for relay L2H,this circuit passing from terminal B, through contact 167 of leverspasm.

L2V, contact 108 of relay 1TR, and the winding of relay L2H to terminalN. Contact 109 of relay L2H will then circuit for lamp R of signal L2,so that signal L2 will now again display a red or stop indication. Whenrelay 1TR becomes deenergized, its contact 76 will open the circuit forrelay RFL and the polar trafiic control relays AFR, BFR, CPR and DFR.With relay RFL deenergized, relay RFLP will in turn be deenergized,because contact 103 of relay RFL Will be open.

When the first westbound train leaves section bc, relay L3TR will againbe energized, as previously traced, by current of the 75 code frequency.Relay L3HR will then again become energized, and yellow lamp Y of signalL3 will again be lighted, as previously described.

When the stretch of track between signals LA6 and RA2 is againunoccupied, and alltlevers are again returned to the n position, allparts of the apparatus will again be in the condition shown in thedrawings.

I shall now assume .that an eastbound traflic movement is to be madeover track X. A leverman or dispatcher will therefore move lever R2V toits r position, thereby completing a pickup circuit for relay RZHSpassing from terminal B, through contact 11% of lever R2V, contact 111of relay RFLP, andthe winding .of relay R2HS to terminal N. Relay RZHS,upon becoming energized by its pickup circuit, completes its stickcircuit passing from terminal B, through contact 112 of lever RZV,contact 113 of relay 1TR, contact 114 of relay R2HS, and the winding ofrelay RZHS to terminal N.

Relays AFR, BFR,"CFR and DFR will now be energized by current of reversepolarity supplied by battery 2Q, shown inFig. 1d, through the winding ofrelay LFL,

I this circuit passing from battery 2Q, through contact 115 of relaySTR, Winding of relay LFL, contact 116 of relay LA6 S, asymmetric unit2i, back point of contact 85 of relay L6HS, front point of contact 84 ofrelay LFK, back point of contact 83 of relay DRFP, winding of relay DFR,conductor 82, winding of relay CPR, conductor 81, winding of relay BFR,conductor 80, winding of relay AFR, front point of contact 79 of relayALFP, front point of contact 78 of relay RZHS, conductor 117, frontpoint of contact 92 of relay RZHS, front point of contact 91 of relayALEP, conductor 90, back point of contact 89 of relay DRFP, front pointof contact 558 of relay LFK, and the back point of contact 87 of relayL6HS to terminal 2N of battery 2Q.

Relay RZHS, upon becoming energized, also completes a circuit forenergizing relay RFK, this circuit passing from terminalB, throughthe'front point of contact 119 of relay R2HS, contact 122 of relay 1TR,and the winding of relay RFK to terminal N. Lever RZV will be returned,by its biasing means, to its 12 position, when the leverman ordispatcher removes his hand from this lever. Relay R2H S will, however,thenbe retained energized by its stick circuit, previously traced.

Relay AFR, upon becoming energized by current of reverse polarity, willmove its contact 12 t the righthand position, thereby deenergizing relayALFP and completing a circuit for energizing relay ARFP, this circuitpassing from terminal'B, through contact 12 of relay AFR closed in theright-hand or reverse position, contact 126 of relay ALFP, and thewinding of relay ARFP in multiple with an asymmetric unit 3i to terminalN.

Relay BFR, upon becoming energized by current of reverse polarity, willmove its contact 16 from the normal position to the reverse position,thereby deenergizing [14 relay BLVP and completing a circuit forenergizing relay BRFP, this circuit passing from terminal B, throughcontact 16 of relay BFR closed in the reverse position, contact 127 ofrelay BLFP, and the winding of relay BRFP to terminal N.

Relay CFR, upon becoming energized by current of reverse polarity, willdeenergize relay CLFP and effect energization of relay CRFP similarly tothe manner in which relay BFR effects deenergization of relay BLFP andenergization of relay BRFP.

Relay DFR, upon becoming energized by current of reverse polarity, willmove its contact 20 to the reverse position, thereby deenergizing relayDLFP.

Relay LFL, upon becoming energized by current of reverse polaritysupplied to relays AFR, BFR, CPR and DFR, will close its contact 129,thereby completing a circuit for energizing relay LFLP, this circuitpassing from terminal B, through contact 129 of relay LFL, and thewinding of relay LFL in multiple with a resistor s and a capacitor 1 toterminal N.

A circuit will therefore now be completed for energizing relay DRFP,this circuit passing from terminal B, through contact 20 of relay DFRclosed in the reverse position, contact 136 of relay DLFP, contact 131of relay LFLP, and the winding of relay DRFP to terminal N. Relay DRFP,upon becoming energized by its pickup circuit just traced, Will completea stick circuit which is the same as the pickup circuit, just traced,except that it includes contact 132 of relay DRFP instead of contact 131of relay LFLP.

The purpose of including a front contact of relay LFLP in the pickupcircuit for relay DRFP is to insure that the contacts of relay LFLP areoperated to the energized position before current can be suppliedthrough contact 134 of relay DRFP to the eastbound track circuit forsection de.

With relay RFK energized and relay ALFP deenergized, the circuit forenergizin relays AFR, BFR, CPR and DFR by current of reverse polaritywill now include the back point of contact 79 of relay ALFP in serieswith the front point of contact 124 of relay RFK, and the back point ofcontact 91 of relay ALF]? in series with the front point of contact ofrelay RFK, instead of including the front points of contacts 79 and 91of relay ALFP as previously traced.

With relay LFLP energized, its contact 72 will be open in the pickupcircuit for relay Lei-IS, so that it will be impossible for a levermanor dispatcher to effect energization of relay Ldl-IS for a westboundtraffic movement While the traflic control relays are energized bycurrent of reverse polarity for an eastbound traflic movement.

With relay DRFP energized, the circuit for energizing the polar trafliccontrol relays by current of reverse polarity will now include thefrontpoint of contacts 83 and 89 of relay DRFP instead of the backpoints of these contacts and the front points of contacts 34 and 88 ofrelay LFK.

With relay DFR energized by current of reverse polarity, its contact 59will be open, and therefore relays L6HR and L61) will be deenergized.With relay BLFP deenergized, relay LBP will also be deenergized by theopening of contact 68 of relay DLFP.

Relay R4TR will now be energized by current of the 75 code frequencypassing rom battery 8 adjacent code transmitter 75CT, shown in Fig. 1d,through contact 19 or this code transmitter 75CT, back point of contact133 of relay RoH, contact 134 of relay DRFP, back point of contact 56 ofrelay DLFP, rail 9 of section d-e, back point of contact 55 of relayCLFP, contact 135 of relay CRFP, winding of relay R lTR, contact 136 ofrelay CRFP, back point of contact 58 of relay CLFP, rail 91: of sectionde, and the back point of contact 57 of relay DLFP, back to battery Withrelay RATR energized by current of the 75 code frequency, relay RiHRwill be energized, but relay R4D will be deenergized. With relay R4HRenergized and relay R4D deenergized, lamp Y of signal R4 will be lightedby a circuit passing from terminal B, through the front point of contact137 of relay R4HR, front point of contact 138 of relay CRFP, back pointof contact 139 of relay R4D, and lamp Y of signal R4 to terminal N.

Relay LSTR will now be energized by current of the 180 code frequency ina circuit passing from battery 8 adjacent signal R4, through contact 11of code transmitter 180CT adjacent signal R4, back point of contact 53of relay CLFP, front point of contact 54 of relay R4HR, contact 140 ofrelay CRFP, back point of contact 48 of relay CLPP, rail 9a of sectioncd, back point of contact 49 of relay BLFP, contact 141 of relay BRFP,winding of relay L3TR, contact 14-2 of relay BRFP, back point of contact46 of relay BLFP, rail 9 of section c-a', back point of contact 47 ofrelay CLFP, and contact 143 of relay CRFP, back to battery 8. With relayLSTR now energized by current of the 180 code frequency, relays L3HR andLSD will be energized, on account of being controlled by contacts 42 and43 of relay L3TR. With relay BLFP deenergized, lamp Y of signal L3 willbe extinguished, and lamp R of signal L3 will be lightedby a circuitpassing from terminal B, through the front point of contact 164 of relayLSHR, back point of contact 105 of relay BLFP, and lamp R of signal L3to terminal N.

Relay RZTR Will now be energized by current of the 180 code frequencypassing from battery 8 at signal L3, through contact 11 of codetransmitter 1853GT at signal L3, front point of contact 144 of relayL3D, front point of contact 44 of relay ERFP, front point of contact 45of relay L3HR, contact 145 of relay BRFP, back point of contact 39 ofrelay BLFP, rail 9a of section b-c, conductor 4'3, front point ofcontact 41 of relay ARFP, winding of relay RZTR, front point of contact36 of relay ARFP, conductor 37, rail 9 of section bc, back point ofcontact 38 of relay BLFP, and contact 146 of relay BRFP, back to battery8. With relay R2TR energized by current of the 180 code frequency,relays RZHR and R2D will be energized by circuits controlled by contact147 of relay APR and the front and back points of contacts 148 and 149of relay R2TR.

With relay R2D now energized, relay RBP will become energized by itspickup circuit passing from terminal B, through contacts 150 and 151 ofrelays ARFP and R21), respectively, and the winding of relay RBP toterminal N. Relay RBP, upon becoming energized, completes a stickcircuit which is the same as the pickup circuit just traced except thatit includes contact 152 of relay RBP instead of contact 151 of relayR2D.

Relay REP, upon becoming energized, completes a circuit for energizingrelay RZI-ISP, this circuit passing from terminal 13, through contacts153 and 154 of relays RBP and RZHS, respectively, front point of contact155 of relay lNWC, back point of contact 156 of relay lRWC, and thewinding of relay RZHSP to terminal N. Relay RAZH will then becomeenergized by a circuit passing from terminal B, through contact 157 ofrelay RZHR, contact 158 of relay 1TR, contact 159 of relay RZI-ISP,contact 160 of relay lNWC, and the winding of relay RAZH to terminal N.With relays RAZH and R21) energized, lamp G of signal RA2 will now belighted by a circuit passing from terminal B, through the front point ofcontact 161 of relay RAZH, front point of contact 162 of relay R2D, andlamp G of signal RA2 to terminal N.

Relay RZHSP, upon becoming energized, opens its contact 22, therebydeenergizing relay RA2S. When an eastbound train enters section a-b,contact 113 of relay lTR will open the stick circuit for relay RZHS,causing relay R2HS to become deenergized. Relay RFK will also bedeenergized by contact 122 of relay lTR. Relays AFR, BFR, CPR and DFRwill then be retained energized by current of reverse polarity in acircuit which is the same as the circuit previously traced forenergizing these relays by current of reverse polarity except that itnow includes the back points of contacts 79 and 91 of relay ALFP and theback points of contacts 124 and of relay RFK instead of the front pointsof contacts 79 and 91 of relay ALFP and the from points of contacts 78and 92 of relay RZHS. The operation of the apparatus as the eastboundtrain now moves over the stretch of track between signals RAZ and LA6will be similar to the operation of the apparatus already described whena westbound train moves' over the stretch of track between signals LA6and RA2.

From the foregoing description of the operation of the apparatus, itfollows that, in apparatus embodying my invention, all of the polartrafiic control relays are retained energized by current of normalpolarity or all of the polar traffic control relays are retainedenergized by current of reverse polarity while a westbound or aneastbound train, respectively, is moving over the corresponding stretchof track.

I shall next assume that the various parts of the apparatus are again inthe condition shown in the drawings, that is, that the polar trafficcontrol relays are deenergized and the contacts of these relays areclosed in the normal position, for example, as shown, and that thestretch of track is unoccupied between signals RAZ and LA6, and alsothat relays R2HS and L6HS are in the deenergized condition. I shallassume further that, with the parts of the apparatus in that condition,an induced surge of current energizes only relay BFR in the reversedirection, causing contact 16 of relay BFR to be moved to the reverseposition. Relay BLFP will therefore be deenergized, and relay BRFP willbecome energized, as previously described.

Battery 8, at signal L3, will therefore be disconnected from section cd,and therefore relay R4TR will be deenergized. With relay R4TRdeenergized, relays R4HR and R4D will also be deenergized, causingbattery 8 at signal R4 to be disconnected from section de.

Relay L6TR will then be deenergized, causing relays L6HR and L6D to alsobe deenergized.

With relay L6D deenergized, relay LFK will become deenergized, therebyconstituting auxiliary means for effecting energization of the polartraffic control relays by current of normal polarity in the circuitpreviously described. The polar contact 16 of relay BFR will thereforebe restored to the normal position, causing relay BRFP to again bedeenergized and causing relay BLFP to again become energized. RelaysR4TR, R4HR, R4D, L6TR, L6HR and L6D will then in turn again becomeenergized.

With relay L6D again energized, relay LFK will also again be energized,thereby opening the auxiliary circuit path for supplying current ofnormal polarity to the polar traflic control relays AFR, BFR, CPR andDFR. All parts of the apparatus will then again be in the conditionshown in the drawings.

I shall now assume that, with all parts of the apparatus again in thecondition shown in the drawings, relay AFR becomes energized in thereverse direction by an induced surge of current which causes thecontacts of relay AFR to be moved to the reverse position. Relay ALFPwill then serve as auxiliary means for effecting energization of thepolar traffic control relays AFR, BFR, CPR and DFR by current of reversepolarity through the back points of contacts 79 and 91 of relay ALFP andthe back points of contacts 124 and 125 of relay RFK.

The contacts of the relays BFR, CFR and DFR also will next be moved tothe reverse position. The track circuits will then be set up for aneastbound traffic movement, as previously described when relay R2HSbecame energized. When relay R2D becomes energized, relay RFK willbecome energized by a circuit passing from terminal B, through contact118 of relay R2D, back point of contact 119 of relay RZHS, contact 122of relay ITR, and the winding of relay RFK to terminal N.

With relay RFK energized, the auxiliary path through the back points ofcontacts 79 and 91 of this relay for effecting energization of relaysAFR, BFR, CPR and DFR by current of reverse polarity will be opened, andthe contacts of all of the relays AFR, BFR, CPR and DFRwill remainclosed in the reverse position. The

apparatus will thus be prepared for an eastbound trafbe either normal orreverse, so that the polar contacts of all the polar trafiic controlrelays will be placed in either the normal position, or all will beplaced in the reverse position.

I shall next assume that all parts of the apparatus are again in thecondition shown in the drawings, and that, in

some way, relays ALFP and LFK become deenergized while relays RFK andDRFP are also deenergized. The polar traflic control relays AFR, BFR,CPR and DFR will therefore be in series in a closed circuit path whichincludes the back points of contacts 79 and 91 of relay ALFP, thebackpoints of contacts 124 and 125 of relay RFK, the back points of contacts$3 and 89 of relay DRFP, and the back points of contacts 84 and 88 ofrelay LFK. This closed circuit path is without any source of current,and therefore the apparatus is in a locked-out or inoperative condition.

' With relay ALFP deenergized, battery 8, shown adjacent codetransmitter 75CT in Fig. la, will be disconnected from section bc, andwith relay DRFP deenergized, battery 8, shown adjacent code transmitter75CT in Fig. 1d, will remain disconnected from section de. With battery8 shown adjacent code transmitter 75CT in Fig. la disconnected fromsection b-c, relay LSTR will be deener'gized. Current of the 75 codefrequency will therefore be supplied from battery 8 at signal L3 tosection cj-d, and therefore relay L6D, shown in Fig. 1d, will bedeenergized.

In order to restore the apparatus to an operative condition, a levermanor dispatcher will manually effect energization of one of the manuallycontrollable signal relays If, for example, a leverman or dispatchershould effect energization of relay R2HS, as previously described, relayRFK would become energized by its pickup circuit previously tracedthrough the front point of contact 119 of relay RZHS.

Since block repeater relay RBP is not energized, route relay RZHSP willnot become energized when the leverman or dispatcher effectsenergization of relay RZHS.

'Since relay RZHSP does not become energized, relay RAZS will not becomedeenergized, and therefore the stick'locking will not become effective;Also, since relay RZHSP does not become energized, relay RAZH will notbecome'energized, and therefore signal RA2 will continue to display thered orstop indication.

The leverrnan'or dispatcher will not deenergize relay RZHS by movinglever RZV to its 1 position and thereby opening its contact 112 in thestick circuit for relay RZHS. Contact 119 of relay RZHS will then becomeopened at its front point, thereby deenergizing relay RFK.

Relay RFK, however, as already pointed out, is slow releasing if itscircuit becomes opened while relay lTR is energized. Relay RFK willtherefore retain its contacts 124 and 125 closed at the front points ina circuit for energizing relay RFL in series with relays AFR, BFR, CPRand DFR by current of normal polarity, until after 18 relay RFL hasclosed its front contact 103 and relay RFLP has in turn becomeenergized. Relay RFLP, upon becoming energized, closes its contact in astick circuit for retaining relay RFK energized, this stick circuitpassing from terminal B, through contact 120 of relay RFLP, contact 121of relay RFK, contact 122 of relay lTR, and the winding of relay RFK inmultiple with the path which includes resistor sk and capacitor tk toterminal N.

When contact 12 of relay AFR becomes closed in the normal position,relay ALFP will become energized by its pickup circuit passing fromterminal B, through contact 12 of relay AFR closed in the normalposition, contact 13 of relay ARFP, contact 15 of relay RFLP, and thewinding of relay ALFP to terminal N. With contact 35 of relay ALFP nowclosed, the track circuits for a westbound trafiic movement will be setup as previously described.

Relay LFK will then again become energized by its pickup circuitpreviously traced, which includes contact 62 of relay L6D. Relay LFK,upon becoming energized, will open its contacts 84 and 88 at their backpoints, thereby opening the circuit previously described for energizingthe polar trathc control relays by current of normal polarity.

With this circuit again opened, relay RFL will become deenergized, andin turn relay RFLP will be deenergized. Relay RFLP, upon becomingdeenergized, opens its contact 120 in the stick circuit for relay RFK,causing relay RFK to also again be deenergized.

It follows that my invention provides an arrangement by which a levermanor dispatcher can restore the ap paratus to an operative condition inthe event of a lockedout or inoperative condition caused by some unusualoccurrence.

It will be noted that, by means of the block repeater relays RBP andLBP, a check of the system is provided after each trafiic controlreversal. The pickup circuit for relay RBP, for example, is controlledby front contacts of relays ARFP and R2D. Before relay RBP can becomeenergized after the traflic control apparatus has been changed fromwestbound control to eastbound control, each of the trafiic controlrelays AFR, BFR, CPR and DFR must have closed its polar contacts in thereverse position, and then the track circuit apparatus must have beenprepared for an eastbound traflic movement in response to the closing ofthe contacts of relays AFR, BFR, CPR and DFR in the reverse position,and the stretch of track must be unoccupied. Relay RBP will then remainenergized until the traific control apparatus is again changed back tothe condition shown in the drawings for controlling westbound traflic.

Although I have herein shown and described only one form of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein within the scope of the appendedclaims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. in railway trafiic controlling apparatus for a stretch of railwaytrack which is provided with a plurality of s gnals for governingtraffic movements in a first direction and in the opposite or seconddirection over said stretch of railway track, embodying a plurality ofpolar trafiic control rela'ys one for each of said signals connected inseries in a traffic control'circuit, each of said relays having polarcontacts which when the corresponding relay becomes deenergized remainclosed in the normal or reverse position to which they were lastoperated in response to current of normal or reverse polarityrespectively, the combination comprising, first manually controllablesignal control means having a normal condition and manually operable toa second condition, second manually controllable signal control meanshaving a normal condition and manually operable to a second condition, afirst trafiic locking relay, a second trafi'ic locking relay, meanscontrolled by said first manually controllable means in its normalcondition and by said second manually controllable means in its secondcondition for supplying current of a given or normal polarity to saidtrafiic control circuit through the winding of said first trafificlocking relay, means controlled by said first manually controllablemeans in its second condition and by said second manually controllablemeans in its normal condition for supplying current of the opposite orreverse polarity to said traffic control circuit through the winding ofsaid second trafiic locking relay, a first trafiic indication relay, asecond traffic indication relay, a first traffic responsive relayenergized by means controlled by contacts of said trafiic control relaysin the reverse position but becoming deenergized in response to a trainentering said stretch in said first direction, a second trafiicresponsive relay energized by means con trolled by contacts of saidtraffic control relays in the normal position but becoming deenergizedin response to a train entering said stretch in said second direction,means controlled by either said first manually controllable means in itssecond condition or by said first trafic rcsponsive relay in theenergized condition for energizing said first tralfic indication relay,means controlled by either said second manually controllable means inits second condition or by said second trafiic responsive relay in theenergized condition for energizing said second trafiic indication relay,means controlled by said first trafiic locking relay in the energizedcondition for retaining said first trafiic indication relay energized,means controlled by said second traffic locking relay in the energizedcondition for retaining said second trafiic indication relay energized,means including back contacts of said first or second trafiic indicationrelay for energizing said trafiic control circuit by current of reverseor normal polarity respectively in response to a train entering saidstretch of track, means including contacts of the corresponding trafiiccontrol relays closed in the normal position for controlling saidsignals for governing trafiic movements in the second direction, andmeans including contacts of the corresponding traffic control relaysclosed in the reverse position for controlling said signals forgoverning traffic movements in the first direction.

2. In railway trafiic controlling apparatus for a stretch of railwaytrack which is provided with a plurality of signals for governingtrafiic movements in a first direction and in the opposite or seconddirection over said stretch of railway track, embodying a plurality ofpolar traflic control relays one for each of said signals connected inseries in a trailic control circuit, each of said relays having polarcontacts which when the corresponding relay becomes deenergized remainclosed in the normal or the reverse position to which they were lastoperated in response to current of normal or reverse polarityrespectively, the combination comprising, first manually controllablesignal control means having a normal condition and manually operable toa second condition, second manually controllable signal control meanshaving a normal condition and manually operable to a second condition, afirst tratfic locking relay, a second trafiic locking relay, meanscontrolled by said first manually controllable means in its normalcondition and by said second manually controllable means in its secondcondition for supplying current of a given or normal polarity to saidtrafiic control circuit through the winding of said first trafiiclocking relay, means controlled by said first manually controllablemeans in its second condition and by said second manually controllablemeans in its normal condition for supplying current of the opposite orreverse polarity to said trafiic control circuit through the Winding ofsaid second traific locking relay, a first traflic indication relay, asecond trafiic indication relay, a first trafiic responsive relayenergized by means controlled by contacts of said tratfic control relaysin the reverse position but becoming deenergized in re sponse to a trainentering said stretch in said first direction, a second trafficresponsive relay energized by means controlled by contacts of saidtraffic control relays in the normal position but becoming deenergizedin response to a train entering said stretch in said second direction,means controlled by said first traflic responsive relay in the energizedcondition for energizing said first tratlic indication relay, meanscontrolled by said second traflic responsive relay in the energizedcondition for energizing said second traflic indication relay, meanscontrolled by said first trafiic locking relay in the energizedcondition for retaining said first traffic indication relay energized,means controlled by said second tratfic locking relay in the energizedcondition for retaining said second trafiic indication relay energized,means including said first or second traffic indication relay in thedeenergized condition for energizing said trafiic control circuit bycurrent of reverse or normal polarity respectively in response to atrain entering said stretch of track, and means including thecorresponding polar trafiic control relays for controlling said signals.

3. in combination, a stretch of railway track, a plurality of signalsfor governing trafiic movements in a given first direction and in theopposite or second direction over said stretch of railway track, aplurality of polar traific control relays one for each of said signalsconnected in series, each of said relays having polar contacts whichwhen the corresponding relay becomes deenergized remain closed in thenormal or the reverse position to which they were last previouslyoperated in response to current of normal or reverse polarityrespectively, first manually controllable means and second manuallycontrollable means each having a normal condition and each manuallyoperable to a second condition, a first trafiic locking relay, a secondtrafiic locking relay, means controlled by said first manuallycontrollable means in its normal condition and by said second manuallycontrollable means in its second condition for supplying current of agiven normal polarity for energizing said first traific locking relayand said polar traffic control relays all in series, means controlled bysaid first manually controllable means in its second condition and bysaid second manually controllable means in its normal condition forsupplying current of the opposite or reverse polarity for energizingsaid second traffic locking relay and said polar traffic control relaysall in series, a first traffic indication relay, a second trafficindication relay, 2. first traffic responsive relay energized by meanscontrolled by contacts of said traffic control relays in the reverseposition, a second trafiic responsive relay energized by meanscontrolled by contacts of said traific control relays in the normalposition, each of said first and second trafiic responsive relaysbecoming deenergized in response to a train moving on said stretch oftrack in said first or said second directions respectively, meanscontrolled by said first trafiic responsive relay in the energizedcondition for energizing said first traffic indication relay, meanscontrolled by said second trafiic responsive relay in the energizedcondition for energizing said second traffic indication relay, meanscontrolled by said first or second traffic locking relay in theenergized condition for retaining said first or second trafficindication relay respectively energized, means including back contactsof said first or second trafiic indication relay for energizing saidsecond or first trafiic locking relays respectively by current ofreverse or normal polarity respectively in series with said polartrafiic control rclays in response to a train on said stretch of track,and means including said trafiic responsive relays for controlling saidsignals.

4. In combination, a stretch of railway track divided into a firstportion adjacent a given first end of said stretch, a second portionadjacent the opposite or second end of said stretch and an intermediatethird portion between said first and said second portions, a first and asecond signal adjacent the first and second ends respectively of saidstretch for governing tratfic movements in opposite directions onto'saidstretch, a first and a second pear, trafiic control relay each havingpolar contacts which when the corresponding relay becomes deenerg'izedremain closed'in the normal or the reverse position to which they werelast previously operated in response to current of normal or reversepolarity respectively, a first trafiic responsive relay energized bymeans controlledby contacts of said trafirc control relays in thereverse position, a second traffic responsive relay energized by meanscontrolled bycontacts of said traific control relays in the normalposition, each of said first and said second traflic responsive relaysbecoming deenergized in response to a'train entering said third portionof said stretch of track at said first or said second end respectively,a third trafiic responsive relay and a fourth traific responsive relayeach normally energized but becoming deenergized in' response to a trainon said first or said second track portion respectively, a first and asecond signal relay, manually controllable means for energizing each ofsaid signal relays, means for then retaining each of said first,and saidsecond signal relays energized cjontrolledby said third or said fourthtraffic responsive re l'ay respectively in the energized condition andalso controlled by manually operable means, a first and a second tralficlocking relay, a first and a second traffic indication relay, meanscontrolled by said first signal relay in the energized condition and bysaid second signal relay in'ithe deenergized condition for energizingsaid second trafiic locking relay and said first and second trafficcontrol relays by current of reverse polarity, means controlled bysaidsecond signal relay in the energized condition and by 'saidfir'stsignalrelay in the deenergized condition for i. energizing said firsttraflic locking relay and said first and second trafiic control relaysby current of normal polarity, a pickup circuit for said first trafiicindication relay controlled by said first and said third trafficresponsive relays in the energized condition, a stick circuit for saidfirst traific indication relay controlled by said third trafficresponsive relay and said first traflic locking relay both in theenergized condition, a pickup circuit for said second traffic indicationrelay controlled by said second and said fourth trafiic responsiverelays in the energized condition, a stick circuit for said secondtraffic indication relay controlled by said fourth traffic responsiverelay and said second trafiic locking relay both in the energizedcondition, means including back contacts of said first or said secondtraific indication relay for energizing said second or said firsttraffic locking relay respectively and said polar trafiic control relaysin response to a train on said stretch of track, and means includingsaid first or said second traffic responsive relay for controlling saidfirst or said second signal a respectively In combination, a stretch ofrailway track, a first and a second signal adjacent the opposite ends ofsaid stretch for governing traffic movements in opposite directions ontosaid stretch, a first and a second polar traffic control relay eachhaving polar contacts which when the corresponding relay becomesdeenergized remain closed in the normal or the reverse position to whichthey were last previously operated in response to current of normal orreverse polarity respectively, first manually controllable signalcontrol means and second manually controllable signal control means eachhaving anormal condition and each manually operable to a secondcondition, a first traffic locking relay, a second traific lockingrelay, a first trafiic responsive relay energizable by means controlledby contacts of said tratfic control relays in the reverse position, asecond trafiic re- Sponsive relay energizable by means controlled bycontacts of said trafiic control relays in the normal position, each ofsaid first and second trafiic responsive relays becoming deenergized inresponse to a train entering said stretch of track at said first or saidsecond signal respectively, a first and a second trafiic indicationrelay, means controlled by said first trafiic responsive relay in theenergized condition for energizing said first trafiic indication relay,means controlled by said second trafiic responsive relay in theenergized condition for energizing said second traflic indication relay,means controlled by said first or second traflic locking relay in theenergized condition for then retaining said first or second trafiicindication relay respectively energized, a first tratfic controlrepeater relay, a pickup and a stick circuit for said first trafficcontrol repeater relay controlled by a contact of said first trafiiccontrol relay in the normal position and the pickup circuit alsocontrolled by said first trafiic locking relay in the energizedcondition, a second tratfic control repeater relay, a pickup and a stickcircuit for said second trafiic control repeater relay controlled by acontact of said second trafiic control relay in the reverse position andthe pickup circuit also controlled by said second traflic locking relayin the energized condition, means controllable by said first signalcontrol means in the normal condition and by said second signal controlmeans in the second condition and by said first and second trafficcontrol repeater relays in the energized and deenergized conditionsrespectively for energizing said first traific locking relay and saidpolar trafiic control relays by current of a given normal polarity,means controllable by said first signal control means in the secondcondition and by said second signal control means in the normalcondition and by said first and second trafiic control repeater relaysin the deenergized and energized conditions respectively for energizingsaid second trafiic locking relay and said polar trafiic control relaysby current of the opposite or reverse polarity, means including saidfirst traffic control repeater relay and said first trafiic indicationrelay both in the deenergized condition for energizing said secondtraffic looking relay and said trafiic control relays by current ofreverse polarity in response to a train on said stretch of track, meansincluding said second trafiic control repeater relay and said secondtraflic indication relay both in the deenergized condition forenergizing said first trafiic locking relay and said traflic controlrelays by current of normal polarity, and means including said first andsecond traflic responsive relays for controlling said first and secondsignals respectively.

6. In combination, a stretch of railway track, a first and a secondsignal adjacent the opposite ends of said stretch for governing trafiicmovements in opposite directions onto said stretch, a first and a secondpolar traffic control relay each having polar contacts which when thecorresponding relay becomes deenergised remain closed in the normal orthe reverse position to which they were last previously operated inresponse to current of normal or reverse polarity respectively, firstmanually controllable signal control means and second manuallycontrollable signal control means each having a normal condition andeach manually operable to a second condition, a first traffic lockingrelay, a' second tratiic locking relay, a first traffic responsive relayenergizable by means controlled by contacts of said traffic controlrelays in the reverse position, a second trafiic responsive relayenergizable by means controlled by contacts of said traflic controlrelays in' the normal position, each of said first and second trafficresponsive relays becoming deenergized in response to a train enteringsaid stretch of track at said first or said second signal respectively,a first and a second trafiic indication relay, means controlled by saidfirst traific responsive relay in the energized condition for energizingsaid first traffic indication relay, means controlled by said secondtratfic responsive relay in the energized condition for energizing saidsecond traific indication relay, means controlled by said first orsecond traflic locking relay in the energized condition for thenretaining said first or second tratfic indication relay respectivelyenergized, a first traffic control repeater relay, a pickup and a stickcircuit for said first traflic control repeater relay controlled by acontact of said first trafiic control relay in 23 the normal positionand the pickup circuit also controlled by said first traflic lockingrelay in the energized condition, a second tratfic control repeaterrelay, a pickup and a stick circuit for said second traflic controlrepeater relay controlled by a contact of said second trafiic controlrelay in the reverse position and the pickup circuit also controlled bysaid second traflic locking relay in the energized condition, meanscontrollable by said first signal control means in the normal conditionand by said second signal control means in the second condition and bysaid first and second traflic control repeater relays in the energizedand deenergized conditions respectively and also by said second traificindication relay in the energized condition for energizing said firsttrafiic locking relay and said polar traflic control relays by currentof given normal polarity, means controllable by said first signalcontrol means in the second condition and by said second signal controlmeans in the normal condition and by said first and second trafliccontrol repeater relays in the deenergized and energized conditionsrespectively and also by said first traflic indication relay in theenergized condition for energizing said second traflic locking relay andsaid polar traflic control relays by current of reverse polarity, meansincluding said first traflic control repeater relay and said firsttraflic indication relay both in the deenergized condition forenergizing said second traflic locking relay and said tratfic controlrelays by current of reverse polarity in response to a train on saidstretch of track, means including said second traflic control repeaterrelay and said second tratfic indication relay both in the deenergizedcondition for energizing said first tratfic locking relay and saidtraffic control relays by current of normal polarity, and meansincluding said first and second trafiic responsive relays forcontrolling said first and second signals respectively.

7. In combination, a stretch of railway track, a first and a secondsignal adjacent the opposite ends of said retc'n for governing trafficmovements in opposite directions onto said stretch, a first and a secondpolar traflic control relay each having polar contacts which when thecorresponding relay becomes deenergized remain closed in the normal orthe reverse position to which they were last previously operated inresponse to current of normal or reverse polarity respectively, firstmanually controllable signal control means and second manuallycontrollable signal control means each having a normal condition andeach manually operable to a second condition, means controllable by saidfirst signal control means in said normal condition and by said secondsignal control means in said second condition for energizing saidtraflic control relays by current of normal polarity, means controllableby said first signal control means in said second condition and by saidsecond signal control means in said normal condition for energizing saidtraffic control relays by current of reverse polarity, a first trafficresponsive relay energizable by means controlled by contacts of saidtraflic control re lays in the reverse position, a second tratiicresponsive relay energizable by means controlled by contacts of saidtratfic control relays in the normal position, each of said first andsecond traific responsive relays becoming deenergized in response to atrain entering said stretch of track at said first or said second signalrespectively, a first block repeater relay, a second block repeaterrelay, means controlled by a contact of said first traflic control relayin the reverse position and by said first traffic responsive relay inthe energized condi tion for energizing said first block repeater relay,means controlled by a contact of said first traflic control relay in thereverse position for then retaining said first block repeater relayenergized, means controlled by a contact of said second tramc controlrelay in the normal position and by said second traflic responsive relayin the energized condition for energizing said second block repeaterrelay, means controlled by a contact of said second traffic controlrelay in the normal position for then retaining said second blockrepeater relay energized, means including said first block repeaterrelay in the energized condition for controlling said first signal, andmeans including said second block repeater relay in the energizedcondition for controlling said second signal.

8. In combination, a stretch of railway track, a first and a secondsignal adjacent the opposite ends of said stretch for governing traflicmovements in opposite ditions onto said stretch, a first and a secondpolar trafiic control relay each having polar contacts which when thecorresponding relay becomes deenergized remain closed in the normal orthe reverse position to which they were last previously operated inresponse to current of normal or reverse polarity respectively, firstmanually controllable signal control means and second manuallycontrollable signal control means each having a normal condition andeach manually operable to a second condition, a first traflic lockingrelay, a second tratfic locking relay, a first traffic responsive relayenergizable by means controlled by contacts of said traffic controlrelays in the reverse position, a second traflic responsive relayenergizable by means controlled by contacts of said traflic controlrelays in the normal position, each of said first and second tratiicresponsive relays becoming deenergized in response to a trainentering'said stretch of track at said first or said second signalrespectively, a first and a second traflic indication relay, meanscontrolled by said first traflic responsive relay in the energizedcondition for energizing said first traflic indication relay, meanscontrolled by said second traflic responsive relay in the energizedcondition for energizing said second traflic indication relay, meanscontrolled by said first or second traflic locking relay in theenergized condition for then retaining said first or second trafficindication relay respectively energized, means controllable by saidfirst signal control means in the normal condition and by sa d secondsignal control means in the second condition for energizing said firsttrafiic locking relay and said trafiic control relays by current ofnormal polarity, means controllable by said second signal control meansin the second condition and by said second signal control means in thefirst condition for energizing said second traflic locking relay andsaid traflic control relays by current of reverse polarity, meansincluding said first traflic indication relay in the deenergizedcondition and said second traflic indication relay in the energizedcondition and also said second manually controllable signal controlmeans in the normal conditionfor retaining said second traflic lockingrelay and said polar trafiic control relays energized by current ofreverse polarity in response to a train on said stretch of track, meansincluding said first traflic indication relay in the energized conditionand said second traflic indication relay in the deenergized conditionand also said first manually controllable signal control means in thenormal condition for retaining said first traffic locking relay and saidpolar traflic control relays energized by current of normal polarity inresponse to a train on said stretch of track, and means including saidfirst or second traflic responsive relay for controlling said first orsecond signal respectively.

9. In combination, a stretch of railway track, a first and a secondsignal adjacent the opposite ends of said stretch for governing traflicmovements in opposite directions onto said stretch, a first and a secondpolar traffic control relay each having polar contacts which when thecorresponding relay becomes deenergized remain closed in the normal orthe reverse position to which they were last previously operated inresponse to current of normal or reverse polarity respectively, firstmanually controllable signal control means and second manuallycontrollable signal control means each having a normal condition andeach manually operable to a second condition, a first 25 traificresponsive' relay energizable by means controlled by contacts of saidtraffic control relays in the reverse position, a second trafiicresponsive relay energizable by means controlled by contacts of saidtrafiic control relays in the normal position, each of said first andsecond trafiic responsive relays becoming deenergized in response to atrain entering said stretch of track at said first or said second signalrespectively, means including said first signal 1 control means in thenormal condition and said second signal control means in the secondcondition for energizing said trafiic control relays by current ofnormal polarity, means including said first signal control means in thesecond condition and thesecond signal control means in the firstcondition for energizing said traffic control relays by current ofreverse polarity, means including said first I trafiic responsive relayin the deenergized condition and said second manually controllablesignal control means in the normal condition for retaining said trafficcontrol relays energizing by current of reverse polarity in response toa train on' said stretch of track, means including said second traflicresponsive relay in the deenergized condition'and said first manuallycontrollable signal control means in the normal condition for retainingsaid traffic,

control relays energized by current of normal polarity in response to atrain on said stretch of track, and means including said first andsecond traflic responsive relays for controlling said first and secondsignals respectively.

10. In combination, a stretch of railway track, a first and a secondsignal adjacent the opposite ends of said I stretch for governingtraffic movements in opposite direc :tions onto said stretch, a first ana second polar trafiic con- I locking relay, a second traific lockingrelay, a first traific responsive relay energizable by means controlledby contacts of said traffic control relays in the reverse position, asecond traflic responsive relay energizable by means controlled bycontacts of said traflic control relays in the normal position, each ofsaid first and second trafiic responsive relays becoming deenergized inresponse to a train entering said stretch of track at said first or saidsecond signal respectively, a first trafiic control repeater relay, apickup and a stick circuit for said first traflic control repeater relaycontrolled by a contact of said first traffic control relay in thenormal position and the pickup circuit also controlled by said firsttraffic locking relay in the energized condition, a second trafficcontrol repeater relay, a pickup and a stick circuit for said secondtraffic control repeater relay controlled by a contact of said secondtrafiic control relay in the reverse position and the pickup circuitalso controlled by said second trafiic locking relay in the energizedcondition, means controllable by said first signal control means in thenormal condition and by said second signal control means in the secondcondition and by said first and second traflic control repeater relaysin the energized and deenergized conditions respectively and also bysaid second traffic responsive relay in the energized condition forenergizing said first traffic locking relay and said polar trafficcontrol relays by current of a given normal polarity, means includingsaid second trafiic esponsive relay and said second trafiic controlrepeater relay both in the deenergized condition for retaining saidfirst traffic locking relay and said polar traffic control relaysenergized by current of normal polarity, means controllable by saidfirst signal control means in the second condition and by said secondsignal control means in the normal condition and by said first andsecond trafiic control repeater relays in the deenergized and energizedconditions respectively and also by said first traffic responsive relayin the energized condition for energizing said second trafiic lockingrelay and said polar traific control relays by current of reversepolarity, means including said first traflic responsive relay and saidfirst trafiic control repeater relay both in the deenergized conditionfor retaining said second trafiic locking relay and said polar trafiiccontrol relays energized by current of reverse polarity, and meansincluding said first and second trafiic responsive relays forcontrolling said first and second signals respectively.

References Cited in the file of this patent UNITED STATES PATENTS2,271,510 Allen Feb. 3, 1942 2,333,974 Bell Nov. 9, 1943 2,366,776Failor Ian. 9, 1945

